The present invention concerns portable objects of small dimensions, such as wristwatches, that comprise a rotating control stem, the actuation of which controls a mechanical or electronic function of the portable object in which the rotating control stem is arranged.
To properly perform the mechanical or electronic function concerned, it must be possible to detect the actuation of the rotating control stem. Among various possible solutions, one consists in measuring the variation in magnetic induction produced by the rotation of a magnet integral with the control stem. To detect this variation in magnetic induction, it is possible to use a magnetic sensor of the Hall effect type which is capable of measuring the value of magnetic induction of the environment in which it is located.
A recurrent problem that arises in the field of detecting the rotation of a control stem by measuring magnetic induction is that of the reproducibility of the measurement from one portable object to another. Indeed, the portable objects referred to here, such as wristwatches, are produced in large quantities on an industrial scale. It is therefore necessary to take steps to ensure the best possible reproducibility of the magnetic induction measurement from one object to another, without these steps adding too much to the final cost price of the portable object. In order to ensure good reproducibility of a magnetic induction measurement, it must be possible to ensure the proper relative positioning of the magnet and the inductive sensor.